Record contained sufficient evidence to support Commission's finding that petitioner violated 29 CFR section 1926.652(a)(1) for failing to provide adequate trench on project to install natural-gas pipeline. While employer disputed Commission's finding as to soil-type that rendered slope of trench too steep, Commission could properly look to proximity of project to busy roadway that subjected nearby soil to vibration, as well as proximity of utility lines to project, to support soil-type finding. Fact that testers did not feel any actual vibration did not require different result.